diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testArgumentsPropLookup.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testArgumentsPropLookup.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+(function() {
+    var s = "__proto__";
+    assertEq(arguments[s], Object.prototype);   
+})();
+
+Object.defineProperty(Object.prototype, "foo", {
+    get:function() {
+        this.bar = 42;
+        return 41
+    }
+});
+
+(function() {
+    var s = "foo";
+    assertEq(arguments[s], 41);
+    s = "bar";
+    assertEq(arguments[s], 42);
+    assertEq("bar" in Object.prototype, false);
+})();